Pump structure



Dec. 24, 1940. H. E. KEMPTON 2,226,285

PUMP STRUCTURE Filed July 10, 1936 4 Sheets-Sheet l H. E. KEMPTON 2,226,285

PUMP STRUCTURE Filed July 10, 1936 4 Sheets-Sheet 2 5 w m 6 W a 0 Q a n 1 7 W m 2 M r y i m 0 2. 0 5 i 2 HH $53 ZN Dec. 24, 1940.

Dec. 24,1940. KEMPTON I 2,226,285

PUMP STRUCTURE Filed July 10, 1936- 4 Sheets-Sheet 3 I fzaeniaz? Patented Dec. 24, 1940 PATENT orrica PUDIP STRUCTURE Herbert E. Kempton, Chicago, 111., usignor to Tuthili Pump Company, Chicago, 111., a corporation of Illinois Application July 10,.

' 2 Claims.

The present invention relates generally to pump structures.

comprises (1) a housing with an inlet and outlet for liquid; (2) a shaft which is iournaled in the housing and is adapted to be drivenby anelectric motor or like power mediiun; and (3) a gear pump which is mounted in the housing and is connected to the shaft so that it operates during l0 drive of the latter to draw liquid through the pressure from the housing via the outlet .until' the motor driven shaft reaches a predetermined rotational speed.

Another object of the invention is to provide a pump structure of the last mentioned character in which the means for rendering the gear pump inoperative or ineflective to pump liquid under pressure from the housing via the outlet comprises a by-pass leading from the outlet or discharge side of the gear pump and also comprises a valvewhich serves to control the flow of liquid under pressure through the by-pass and is controlled automatically and in such manner that it remains open during drive of the shaft below the aforementioned predetermined rotational speed.

A further object of the invention is to provide a pump unit of the type and character under consideration which has particular utility in connection with an oil burner of the nozzle and blower type and is adapted to have the shaft for driving the gear pump connected to the impeller wheel of the burner blower for conjoint drive therewith.

A still further object of the invention is to provide a pump structure which is generally of new and improved construction, embodies a novel arrangement of parts, and is extremely efiicie'nt in operation.

Other objects of the invention and the various advantages and characteristics of the present pump structure will be apparent from a consideration of the following detailed description.

The invention consists in the several novel features which are hereinafter set forthand are more particularly defined by claims at the conclusion hereof.

In the drawings which accompany and form a part of this specification or disclosure and in More particularly the invention relates to that type of pump structure which.

1936, Serial No. 89,913

which like numerals of reference denote corresponding parts throughout the several views:

Figure 1 is a view partly in elevation and partly in section of'an oil burner and a pump structure embodying one from of the invention;

Figure 2 is a horizontal section on the line 2-4 of Figure 1;

Figure 3 is a vertical longitudinal section of the pump structure of Figure 1;

Figure 4 is a vertical transverse section on the line 4-4 of Figure 3;

Figure 5 is a vertical transverse section taken on the line 5-5 of Figure 3 and showing the plate which is connected to one end of the pump housing and forms with the latter a chamber for the operating parts of the gear pump;

Figure 6 is a plan view of the plate shown in Figure 5;

Figure 7 is a vertical transverse section taken on the line 1--| of Figure 3 and showing the construction of the gear pump;

Figure 8 is a horizontal section on the line 8-8 of Figure 7; V

Figures 9 and 10 are horizontal'sections on the lines 9-9 and Ill-l0 of Figure 3, respectively.

Figure 11, is a vertical longitudinal sectional view of a pump unit embodying another or second form of the invention;

Figure 12 is a detail sectional view of the automatic pump controlling means of the pump structure of Figure 11; and

Figure 13 is an enlarged vertical transverse sectionon the line 13-43 of Figure 11.

The pump structure which is shown in Figures 1, 2, 3, 4, 5, 6, 7, 8, 9 and i0 constitutes one embodiment of the invention and is adapted for use in connection with. an oil burner B. It is of the internal gear type and operates, as hereinafter described, to draw oil from a tank T and force it under pressure to' a nozzle b which forms a part of the burner B. As shown in Figures 1 and 2 the burner B embodies, in addition to the nozzle b, a blower b and an electric motor b for driving the blower. The blower consists of an impeller wheel b and a casing b around the wheel and operates during drive thereof by the motor to supply air under pressure around the nozzle b. The impeller wheel b of the blower is fixed to a horizontally extending shaft b and embodies an annular series 01. blades b" on the peripheral portion thereof. The.casing b of the blower surrounds the impeller wheel b and embodies a pair of end walls 12'' and b and a tubular tangentially extending discharge member 11. The end wall 11' of .the blower casing laps one 'plied by the pump structure is located in the outer end of the tubular discharge member b. When the impeller wheel b is driven air is drawn into the central portion of the casing through the inlet opening b in the end wall b' and is discharged under pressure through the discharge member b One end of the shaft b is journaled in a bearing Z1 in the end wall b" of the blower casing and is connected in any suitable manner to the armature shaft of the electric motor b. The other end of the shaft extends through the inlet opening D in the end wall I: of the blower casing and is connected to the pump structure so asto drive the latter. The electric motor b is encased in a housing Ir which is fixed to the end wall b of the blower casing b When current is supplied to the electric motor b the shaft b is driven and operates both the blower and the pump structure. When the pump structure operates to supply oil under pressure to the nozzle b of the burner the oil is atomized by the nozzle and forms a combustible mixture with the air which isdelivered by the blower through the tubular discharge member b. This mixture is adapted to be ignited by way of a pair of electrodes b" in the outer or discharge end of the tubular member b These electrodes receive current through the medium of a pair of conductors b and are spaced apart for spark forming purposes, as shown in Figure 2.

The pump structure comprises a pump housing I1, an internal gear pump |8, a strainer I8, and a valve unit 20, and is characterized by the fact that it includes novel and simple means whereby it is controlled so that no oil is supplied to the nozzle b of the burner B unless the shaft 17 is.

driven at normal speed by the electric motor b. By incorporating means of this character in the pump structure the burner, during starting thereof, receives no oil until the blower is operating at its normal speed and there is a. liberal or proper supply of air around the nozzle 1). Furthermore, the flow of oil to the nozzle is automatically cut off or stopped before stoppage of the air supply when the burner is shut ofi or rendered inoperative by cutting off the flow of cur-' rent to the electric motor b. The pump housing I! of the pump structure is in the form of an elongated horizontally extending metal casting and is carried by a frame 2| so that it is coaxially positioned with respect to the electric motor b for driving the impeller wheel of the blower. The frame 2|, as shown in Figure 1 of the drawings, is fixed to the end wall b 01' the blower casing b and includes a vertically extending wall 22. The latter is spaced from said end wall b by way of. top and bottom walls 23 which includeopenings for permitting the flow of air to the inlet opening U The pump housing ll extends through a hole 24 in the vertically extending wall 22 of the frame 2| and embodies a radially extending flange 25. The latter is formed integral- 1y with the central portion of the pump housing and fits against the outer face of the wall 22. Bolts 28 extend through the flange 25 and the vertically extending wall 22 and serve to holdthe pump housing II in fixed or connected relation with the frame 2|. The inner end of the pump housing is cylindrical and has an enlarged bore 21 which forms a centrifugal valve chamber 28 and extends longitudinally of the pump housing. The other or outer end of the pump housing I! plug 3| fits in the bore 38, as shown in Figure 3,

and has a longitudinally extending eccentrically disposed bearing forming hole 32. The inner end of the plug projects into the centrifugal valve chamber 28 and is in the form of a reduced extension 33. The other or outer end of the plug terminates inwardly of the flat outer end face 29 of the pump housing and forms with the outer end of the bore 38 a cylindrical chamber 34 in which the operating parts of the internal gear pump are disposed. The outer end of the shaft b that is the end of the shaft which extends through the inlet opening 22 in the end wall b of the blower casing projects through the bore 21 in the inner end of the pump casing l1 and extends into and is journaled in the bearing forming hole 32 in the cylindrical plug 2|. The inner end of the pump housing I! is closed by means of a fluid tight sealing device 35. The

latter serves as an end closure for the boreformed centrifugal valve chamber 28 and includes a ring 38 which extends around the shaft b and has an external screw thread in engagement with an internal screw thread in the bore- 21. The pump housing I! of the pump structure embodies in addition to the outward or radially extending flange 28 a transversely extending suction port 31 in one side thereof, and a transversely extending by-pass port 38 in its other side. These two ports are positioned one diametrically opposite the other and are located in the lower portion of the pump housing H. The suction port is connected to the oil tank T by a pipe 39 and the by-pass port 38 of the pump housing I1 is connected to the tank by a pipe 40. During operation of the pump structure oil is drawn from the tank T through the pipe 39 and into the pump housing I! via the port 31 and then after being drawn through the strainer l9, as hereinafter described, passes to the suction side of the internal gear pump. From the pressure side of the pump the oil is either by-passed back to the tank T via the by-pass plate 38 and the pipe 40, as hereinafter described, or is delivered to the valve unit 20 and there flows part to the burner nozzle b and the remainder via the pipe 48 to the tank T.

The internal gear pump I8 is of standard design or construction and consists of a gear 4|, a rotor 42, and a crescent 43. The gear 4| of the pump is disposed in the chamber 34 in the outer end of the pump housing I! and is keyed or oth-..

erwise fixedly secured to the shaft b Due to the fact that the bearing forming hole 32 is cocentrically disposed in the plug 3| the gear 4| of the pump is eccentrically positioned in the chamber 34. The rotor 42 corresponds in diameter to, and fits within, the chamber 34. It is in the form of an internally toothed ring type gear and surrounds and meshes with the gear 4|, as shown in Figure 7. The crescent 43, as shown in Figure 7, is stationary. It is formed as an integral part of the plug 3| and fits it and seals the crescent shaped space between the gear 4| and the rotor 42, that is the space where the teeth of the gear are not in mesh with the teeth of the rotor due to the eccentric position of the gear with respect to the rotor. The chamber 34 in which thegear, rotor and crescent of the internal gear pump are disposed is closed at the outer end thereof by means of a plate 44. This plate fits against the flat end face 29 of the pump housing I! and is secured in place by means of a series of bolts 45. Thelatter extend through holes 45 in the plate 44 and project into internally threaded sockets 41 in the outer end portion of the pump housing il. As shown in Figure 5,'the plate 44 embodies in the central portion thereof a pair of oppositely facing kidney-shaped.

slots 44 and 48. The slot 48 is located adjacent to and communicates with one side of the chamber 84 in the outer end of the pump housing I1 and forms the pump inlet. The slot 48 is located adjacent to, and communicates with, the other side of the chamber 34 and constitutes or forms the pump outlet. The inlet of the pump, that is the kidney-shaped slot 48 communicates with the strainer i9, and the pump outlet communicates with and discharges into the valve unit 20, as hereinafter described. When the shaft 11 is rotated by the electric motor I) the gear and rotor, due to the fact that they are in mesh, revolve within the chamber Y34 and the pump is thus caused to operate. During operation of the-pump a partial vacuum is created in the inlet forming kidney-shaped slot 48 in the plate 44. This is'attributable to the fact that as the teeth of the gear 4! come out of mesh with the teeth of the rotor 42 here is a sucion action in the inlet side of the pump. In response to this action, oil is sucked or drawn from the tank through the pipe 39 and the strainer 19 and flows into the space between the teeth of the gear and the rotor. When the teeth oi the gear 4i mesh with the teeth of the rotor 42 at the outlet side of the pump the aforesaid spaces are filled and the oil is forced under pressure out through the outlet forming kidneyshaped slot 49 in the plate 44 and is delivered to the valve unit 20, as hereinbefore described.

The strainer l9 through which the oil passes in transit from the suction port 31 to the internal gear pump I8 is located beneath the outer end of the pump housing I1 and comprises a cupshaped casing 50 and a series of screen units 5i. The casing 50 is secured in place by means of a bolt 52 which extends upwardly through the bottom of the casing and fits within an internally threaded socket 53 in the bottom portionof the front end of the pump housing H. A gasket 54 is interposed and clamped between the upper margin or edge of the side wall of the casing and the bottom face of the pump housing and serves to prevent leakage of oil from the casing. The units 5| are arranged in superposed relation in the casing 50 and each consists of an outer frame 55, an inner frame 56, and a screen 51 between the two frames. A plate 58 on the shank part of the bolt 52 and a compression spring 59 between theplate and the bottom of the strainer casing 50 serve to hold the screen units in clamped relation and to urge them upwards against the bottom face of the outer portion of the pump housing H. The inner frames 55 of the screen units 5i have aligned holes 60 therein through which the shank portion of the bolt-52 extends. They are centrally positioned with respect to the outer frames 55 and have offset portions with aligned apertures 6i therein. These apertures 6i communicate with a duct 62 leading downwards from the suction port 31 in the pump casing and permit oil inv response to the suction created by the internal gear pump to flow through an aperture (not shown) in the plate 58 into the strainer casing 50. The screens 51 of the units are arranged to form inlet compartments 54 and outlet compartments 65. The inlet compartments are arranged in alternate relation with respect to 50; grooves 66 in the outer frames of the screen the outlet compartments and receive oil from the container casing byway of duct forming grooves It in the outer frames 55 of the units. The oil after passing through the grooves into the inlet compartmentsflflowsthroughthe screens 5': into a the outlet compartments 4! and then passes into aligned apertures 61 in the outer frames 55 of v the units. The apertures 61 communicate with the outlet compartments 85 by way of pairs of grooves 88 in the outer frames of the units and communicate with a vertically extending passage 68 in the bottom portion of the outer end of the pump housing-l1. The inlet forming kidneyshaped slot 48 in the plate 44 communicates with the passage 59 by way of a horizontally extending passage 10, an arcuate groove H, a hole 12 and a groove 13. The horizontally extending passage 10 is formed in the outer'end of the pump housing l1 and leads from the upper end of the vertically extending passage 68 to the flat end face 29 of the pump housing where it joins and communicates with the arcuate groove H. The latter is formed in thefiat end'face 29 of the pump housing and as shown in Figure '7, underlies the chamber 34 in which the operating parts of the internal gear pump are disposed. The hole 12 is formed in the plate 44 and, as shown in Figure. 5, is positioned directly beneath the inlet forming kidney shaped slot 48 and so that it registers or communicates with one end of the arcuate groove 1| in the fiat end face 29 of the pump housing. The valve unit 20 is located adjacent to the outer end of the pump housing i1 and comprises a body I4. The latter extends vertically and has a flat'face 15 which abuts against the outer face of the plate 44. The body of the valve unit is held in place by means of the bolts 45 which, as shown in Figure 10, extend through holes 16 in a pair of laterally projecting lugs 11 on the valve body ands operate to hold the flat face 15 in clamped relation with the outer face of the plate 44. Thegroove 13 is formed in the central portion' of the flat face 15 of the body Hi and includes a pair of arcuate branches l3 and 13 The branch 13*- communicates with the branch I3 and is positioned so that-one end thereof reg, isters with the hole I2 in the plate 44. The branch 13 'of the groove 13 registers with the kidney-shaped slot 48 in the plate 44 and assists the latter in forming the inlet for the internalf gear pump I8. When the pump is in operation as the result of drive of the electric motor I: suc'-" tion is created in the kidney-shaped slot 45in plate 44, as previously pointed out,.and as a r suit of this suction oil flows from'tank T into ,t' inlet or suction side of the pump asfollowsf pi 39; suction port 31; ductti; apertures Si in the inner frames of the screen units 55 of the strainer l9; aperture 63 in the plate 58; interior of easing units; inlet compartments 64; outlet comparto0 ments 55; grooves 68 and aligned apertures 61 in the outer frames ofthe screen units; passages 59 and 10; groove 1i; hole 12; and branches l3 and I3 of groove 13.

Thevalve unit 20 is connected by a pipe 18 to supply 011 under pressure from the internal gear pump l8 to the nozzle b of the oil burner and comprises in addition to the body 14 a plunger type valve 19 and a sleeve type valve seat 80. 70

The body 14 is provided with a vertically extending bore 8i in which the plunger type valve I9 is slidably'mounted. The valve seat is located in the lower end of the bore 8i and is carried by a plug 82 at the lower end of the body 14. The shank of the plug, as shown in Figure 3, has a centrally disposed vertically extending hole 83 and is provided with an external screw thread in engagement with an internal screw thread in the lower end of the bore. The upper end of the hole 83 is enlarged and forms a socket 84 for the valve seat 88. The pipe 18 is connected to the lower end of the plug 82 by means of a coupling ring 85 and a vertically extending nipple 88. The upper end of the nipple communicates with the hole 83 and fits within an internally threaded socket 81 in the lower end of the plug. The coupling ring 85 surrounds the inlet end of the pipe 18 and serves to connect the pipe to the lower end of the nipple. The portion of the bore 8| which is disposed directly above the plug and sleeve type valve seat is shaped to form an enlarged pressure chamber 88. This chamber communicates with, and receives oil from, the pressure side of the internal gear pump I8, as hereinafter described. The valve 19 is located above the pressure chamber and is urged downwards into seated relation with the valve seat 88 by means of a compression spring 89. When oil is delivered into the pres- 'sure chamber 86 under such pressure that it raises the valve against the force of the spring 89 it flows from the pressure chamber to the nozzle b via the sleeve type valve seat 88, the ver centric arcuate branches 93 and 93 tically extending hole 83 in the plug 82, the nipple 96, and the pipe 18. The compression spring 89 is located in the upper end of the bore 8I and abuts against and extends between the valve 19 and an adjusting screw 98. The latter extends through the upper end of the body 14 of the valve unit 28 and is secured or fixed in its various adjusted positions by means of a lock nut 9| which fits against the top face of the body 14 and is' housed in a cap 92. By adjusting the position of the screw 98 the compression "of the spring 89 may be increased or decreased in order to increase or decrease the amount of pressure necessary to unseat the valve 19. The pressure chamber 88 communicates with and receives oil from the kidney-shaped slot 49 which forms the outlet or pressure side of the internal gear pump I8 by way of a groove 93, a hole 94, a groove 95, a hole 96, and a duct 91. The groove 93 is formed in the fiat face 15 of the body 14 of the valve unit. It is positioned directly opposite the groove 13 and comprises a pair of substantially con- The branch 93 registers with the kidney-shaped slot 49 in the plate 44 and assists said slot in forming the outlet or discharge side of the gear pump I8. The branch 93 communicates with the branch 93 and registers with the hole 94 which, as shown in Figure 5, is formed in the plate 44. The groove 95 is formed in the fiat face 29 at the outer end of the pump housing I1 and is located at one side of the chamber 34 and the arcuate groove One end of the groove 95 registers with the .--hole 94 and the other-end registers with the hole The latter, as shown in Figure 5, is formed in the plate 44 and is disposed between and beneath the hole 94 and the outlet forming slot 49. The duct 91 is inclined and leads from the hole 96 to the pressure chamber. When the gear pump I8 is in operation as the result of drive of the electric motor b the oil which is discharged under pressure by the pump flows to the pressure chamber 88 in the body of the valve unit 28 as follows: kidney-shaped slot 49 in the plate 44; branch 93 of the groove 93 in the flat face of the body 14 of the valve unit; branch 93 of the groove 93; hole 94 in the plate 44; groove 95 in the flat face 29 at the outer end of the pump housing I1; hole 86 in the plate 44; and inclined duct 91 in said body 14. When the pressure in the chamber 88 is suiiicient to raise and unseat the plunger type valve 19 oil under pressure flows from the chamber to'the nozzle b of the burner, as hereinbefore described. In order to permit of the ready discharge to the by-pass port 38 of the excess oil under pressure delivered by the pump into the pressure chamber 88, a horizontally extending passage 98, a hole 99, and an inclined diagonally extending duct I88 are provided. The passage 98 is formed in the body 14 of the valve unit 28 and, as shown in Figure 3, is located a small distance above the pressure chamber 88. It extends or leads from the bore 8| to the fiat face 15 of the body 14 and is closed'by the plunger part of the valve 19 when the valve is in its closed position. The hole 99 is formed in the plate 44 between and slightly beneath the holes 12 and 96 and registers with the passage 98. The duct I88 is formed in the outer end of the pump housing I1 and leads from the hole 99 in the plate 44 to the by-pass port 38. When the valve 19 is forced upwardly into its open position as a result of the pressure of the oil in the chamber 88 the passage 98 is uncovered and the oil in the pressure chamber flows part to the burner nozzle b via the pipe 18 and part to the tank T via the passage 98, the hole 99, the duct I88, the by-pass port 38, and the pipe 48. By bypassing back to the tank a portion or part of the oil which is delivered to the pressure chamber 88 in the valve unit 28, constant pressure of the oil is maintained at the nozzle of the burner.

The means for controlling the pump structure so that no oil is supplied to the nozzle b of the burner unless the shaft 1) is driven at or in excess of a predetermined speed by the electric motor 1) comprises a sleeve valve IN, a plurality of balls I82, and a ball controlled thrust member I83. The valve I8I is disposed in the centrifugal valve chamber 28 in the inner end of the pump housing I1. It is slidably mounted on the shaft b and serves to control the entry of oil under pressure into the centrifugal valve chamber 28 from an annular groove I84 in the shaft b Oil under pressure is adapted to flow from the outlet or pressure side of the internal gear pump I8 to the groove I84 by way of a groove I85, a duct I86, and a plurality of holes I81. The groove I85 is formed in the inner face of the plate 44 and communicates with and receives oil from the outlet formingkidney-shaped slot 49 in said plate. The duct I86 is formed in and extends longitudinally through the outer end of the shaft b that is the end of the shaft which is, disposed in the pump housing I1. One end of the duct I88 extends through the extreme outer end face of the shaft and registers with the groove I85 in the plate 44, and the other end of the duct communicates with the groove I84'by way of the holes I81 which are formed in and extend radially with respect to the shaft aaaaass from the outlet or discharge side of thecentrifugal gear pump I8 through the groove I08 to the longitudinal duct I08 in the shaft b, and then flows outwardly through the radially extending holes I01 and the annular groove I04 into the chamber28. From this chamber the oil flows via the duct I08 to the by-pass' port 38 and thence through the pipe 40 to the tank. Be-

cause of the flow of oil to the by-pass port when the valve MI is in its open position, there is not sumcient pressure in the pressure chamber 88 of the valve unit 20 to raise the plunger type valve I9 and hence there is no flow of oil from the pump I9 to the nozzle of the burner. When the valve IOI is in its closed position so that it overlies or covers the annular groove I04 the flow of oil-from the outlet or discharge side of the pump to the chamber 28 is cut oif and all of the oil which is pumped by the pump is delivered to the pressure chamber 88 from whence it flows part to the burner B and part back to the tank T via the passage 88, the hole 89, the duct I00, the by-pass port 38, and the pipe 40, as hereinbefore described. The halls I02 in conjunction with the ball controlled thrust member I08 operate automatically to shift the valve into its closed position when the shaft b reaches its proper rotational speed, and a compression spring I09- operates to shift the valve into its open position when the speed of the shaft 12 is below normal. The balls I02 are mounted in an annular carrier IIO which is fixed to rotate with the shaft b and embodies radially extending pockets I II for the balls. As shown in Figure 3, the balls are loosely mounted in the pockets and are adapted during rotation of the shaft and the carrier, and in response to centrifugal force or action, to fly outwards. The pockets III extend around the inner end of the valve IOI. The thrust member I03is annular and is formed integrally with the central portion of the sleeve valve I M and embodies a conical or cam type wall H2. The latter bears against the outer portions of the balls I02, as shown in Figure 3. The ball controlled thrust member and the sleeve valve are suitably held against rotation but are free to slide or move lengthwise of the shaft. During drive of the shaft 17 the carrier H and the balls I 02 rotate. When the speed of the shaft is such that the centrifugal force of the balls I02 is suificient to overcome the action of the compression spring I09 the .balls fly or move outwards and due to the cam action of the wall II2 shift the thrust member towards the outerend of the pump housing I and. thus shift the sleeve valve into its closed position. When the speed of the shaft b decreases as theresult of stoppage of the electric motor I) or for any other reason, the spring I09 overcomes the centrifugal action of the balls I02 and shifts the'thrust member together with the sleeve valve towards the ring 36 of the sealing device 35 into a position wherein the annular groove I04 in the shaft 1) is exposed and the internal gear pump, as the result of by-passing of the oil via the chamber 28 and the passage I 08 is thus inoperative to pump oil through the nozzle b of the burner. The spring I09 surrounds the shaft b and fits between a pair of rings H3 and H4. The ring II3 fits around and is slidably mounted on the reduced extension 33 at the inner end of the plug 3| in the bore 30. The ring H4 is mounted on the end of the sleeve valve that is nearer the annular groove 104 in the shaft 12 and abuts against the ball controlled thrust member I03.

Pin and slot connections I Il between the two rings serve to hold the rings against relative rotation but permit them to move to and from one another. In order to adjust the compression of the spring I09 a screw H8 is provided. This screw extends through the top wall of the pump housing I1 and abuts against a tapered surface ill on the ring II8. When the screw is turned so that it moves toward the ring I I3, said ring in response to the action of the tapered surface III moves axially toward the ring Ill and increases the compression of the spring I09. When the screw is moved in the opposite direction,

that is away from the ring H3, thering is permitted to move away from the ring Ill and this results in a decrease in the compression of the spring I09. When the compression of the spring is increased the force tending to counteract the centrifugal action of the balls I02 is increased with the result that the shaft 1; must rotate at a higher speed before the sleeve valve IN is caused by the balls and the thrust member to move into its closed position wherein it shuts off the by-passing of oil to the by-pass port 38 and causes .the internal gear pump I8 to supply oil unit 20 the spring force tending to counteract the centrifugal action of the balls I02 is lessened or decreased with the result that it is not necessary for the shaft to rotate at such a high speed before the balls and carrier operate to shift the sleeve valve IN into its closed position. The ring H8 and the screw II8 exemplify a simple instrumentality for setting the speed at which the shaft must rotate before oil is pumped by the internal gear pump I8 to the nozzle b of the burner.

The operation of the pump structure of Figures 1 to inclusive is as follows: When the shaft 1) is stationary and the burner B is hence inoperative the plunger type valve I9 of the pump unit is closed and the sleeve valve IOI on the shaft b due to the action of the compression as the shaft b starts to rotate the impeller wheel b of the blower b operates to draw air through the inlet opening b into the blower casing b and to force the air under pressure through the tubular discharge member I: and thence around the burner nozz e 2). In addition the internal gear pump I8 starts to draw oil from the tank T through the pipe 39, the suction port 31, the strainer I9, and the passageway consisting of passages 89 and I0, groove II, hole I2, grooves I3 and slot 48, and to force the oil undr pressure into the outlet forming kidney-shaped slot 49 in the plate 40. From this slot oil under pressure flows through the groove I05, the duct I09, the cross-holes I01 and the groove I00, into the centrifugal valve chamber 28 and thence via the passage I08 to the by-pass port 38 from whence it flows through the pipe 40 back to the tank T. During the initial or slow speed drive of the shaft b and while the sleeve valve I9 of the valve unit 20 remains closed and no oil flows from the pressure chamber 88 to the nozzle b of the burner. As soon as the shaft b reaches such a speed that the centrifugal action of the balls I02 is suflicient to overcome the action of the compression spring I09 the balls move outwards and in response to the cam action of the tapered wall I I2 shift the thrust member m3 towards the valve unit 20 and thus bring the sleeve valve IBI into its closed position. As soon as the valve IN is shifted into such position bypassing of the pumped oil through the chamber 28 and thence to the by-pass port 38 via the passage I08 ceases and the oil under pressure flows from the outlet side of the pump to the pressure chamber 88 via the passageway consisting of slot 49, groove 93, hole 94, groove 95, hole 96, and duct 91. As soon as the pressure in the chamber 88 is sufiicient to collapse the compression spring 89 of the valve unit 20, the plunger type valve 19 moves upwards in the bore BI and oil under pressure flows from the chamber 88 through sleeve type valve seat 80, hole 89, nipple 88, and pipe 18 to the nozzle 17 of the burner. Due to the automatic action of the valve IN the gear pump I does not operate to supply oil to the nozzle b of the burner until the shaft b reaches a comparatively high speed and the blower operates to supply a liberal amount of air around the nozzle. By having a liberal supply of air around the burner nozzle 12 prior to delivery of the oil by the gear pump to the nozzle b it is impossible especially during starting of the burner to have an over-rich explosive type of mixture emanating from the tubular discharge member b of the blower casing of the burner. When the burner is shut down by closing the switch for the motor lg, the shaft b comes gradually to rest as a result of the fly-wheel action of the impeller wheel and the armature of the motor. As soon as the speed of the shaft b drops to such an extent that the compression spring I09 is suflicient to overcome the centrifugal action of the balls I02 the spring shifts the thrust member I03 in the direction of the inner end of the pump casing I1 with the result that the balls I02 are caused to move inwards and the sleeve valve IN is caused to move into its open position. Upon opening of the valve IOI communication is established between the annular groove I04 in the shaft 1) and the bore formed centrifugal valve chamber 28 in the inner end of the pump housing I1 and as a result the oil which is pumped by'the pump is by-pas'sed back to the tank T, as hereinbefore described, and does not flow through the pipe 18 to the burner nozzle. By automatically stopping the flow of oil immediately upon stoppage of the flow of current to the electric motor I: and while the impeller wheel b of the blower is still revolving or in operation there can be no free oil or unburnt oil vapor at the discharge end of the burner. By adjusting the screw IIS the pump structure may be set so that the gear pump .is operative to supply oil under pressure from the valve unit 20 when the shaft b reaches any desired rotational speed.

In order to vent the space above the plunger type valve 19 of the valve unit 20 and thus permits said valve 19 readily to move upwards when the sleeve valve IN is closed 'and pressure develops in the enlarged pressure chamber '88, a passageway II8 between the centrifugal valve chamber 28 and the upper end of the bore BI is provided. This passageway consists of a longitudinally extending duct H9 in the upper portion of the outer end of the pump housing I1, a hole I20 ,in the plate 44 and an inclined duct I2I in the upper end of the body 14 of the valve unit.

The pump structure which is shown in Figures 11, 12 and 13 constitutes another form or embodiment of the invention. It is adapted to be used in connectionwith an oil burner in the same manner as the pump structure of Figures 1 to inclusive, and comprises a pump housing I1 an internal gear pump I8, a strainer I9, and a valve unit 20. The pump housing I1 is exactly the same in design and construction as the housing I1 of the pump structures of Figures 1 to 10 inclusive and embodies a centrifugal valve chamber 28 in the inner end thereof and a plug 3| in its outer end. The plug 3 I has a chamber 34 for the various operating parts of the internal gear pump I8, and also has a longitudinally extending bearing forming hole 32 in which is journaled the outer end of the impeller driving motor driven shaft of the burner with which the pumping unit is associated. As shown in Figure 11, the end of the shaft which is iournalled in the hole 32 has an annular groove I04, a longitudinal duct I06 between the groove and the pump I8, and a plurality of radially extending holes I01 between the inner end of the duct I06 and the groove I 04. The housing I1 of the pump structure embodies a suction port (not shown) in one side thereof and a by-pass port 38 at the other side thereof and has a passage I08 between the centrifugal valve chamber 28'- and the by-pass port 38*. The duct I06, the cross-holes I01, the annular groove I04, the centrifugal valve chamber 28, and the passage I08 constitute a by-pass connection between the outlet or discharge side of the centrifugal pump I8 and the by-pass port 38. The internal gear pump I8, the strainer I9, and the valve unit 20*, are respectively the same in design and construction as, and operate similarly to, the gear pump, strainer and valve unit of the pump structure of Figures 1 to 10 inclusive. A plate 44* corresponding in design to the plate 44 of the previously described pump structure fits between the outer end face of the pump housing I1 and the body of the pump unit 20. Said pump unit 20 includes a plunger type valve 19, and a sleeve type valve seat 80, and has a pressure chamber 88, which is connected to the discharge side of the gear pump.

The pump, structure of Figures 11, 12 and 13 is exactly the same as that of Figures 1 to 10 inclusive, with the exception that it embodies different means for controlling the by-passing of oil under pressure from the outlet or discharge side of the internal gear pump to the by-pass port of the pump housing. The control means 01 the pump, structure of Figures 11, 12 and 13 comprises a disk-like valve housing I22, and a pair of valve plungers I23. The housing I22 is disposed in the centrifugal valve chamber 28' in the pump housing I1- and extends around and is lfixed to rotate with the motor driven shaft. As shown in Figure 11, the housing surrounds the annular groove I04 in the shaft and includes, a pair of diametrically opposite radially extending cylinders I24. The valve plungers I23 flt slidably in these cylinders and are adapted during drive of the shaft and in response to centrifugal force to move outwards in the cylinders. The outer'ends of the cylinders open into the centrifugal valve chamber 28, and have compression springs I25 for urging the valve plungers I23 inwardly towards the shaft. A spring ring I28 fits in an annular groove I21 in the outer periphery of the housing I22 and forms abutments for the outer ends of the springs I 25. The housing I22, as shown in Figure 11 embodies at one side of the cylinders I24 a pair'of diametrically opposite radially extending ducts I28. These ducts extend alongside of the cyllndersl and communicate at their inner ends with the annular groove III4 in the motor driven shaft. The outer ends of the ducts I28 extend at right angles and lead to, and communicate with, the outer ends of the cylinders for the valve pistons I28. When the motor driven shaft is at rest and the valve pistons are in engagement with the shaft, as shown in Figure 11, the outer ends of the ducts are uncovered or exposed and there is communication between the annular groove II) in the shaft and the centrifugal valve chamber 28'. When the shaft is rotated at such a speed that the valve plungers I23 move outwards against the force of the springs I 25, the outer ends of the ducts I28 are covered or closed, as shown in Figure 12, and by-passing of the oil from the internal gear pump I8 through the valve chamber.

28 to the by-pass port 38 is terminated.

The operation of the pump structure of Figures 11, 12 and 13 is as follows: When the motor driven shaft starts to rotate, the oil which is pumped by the gear pump I8 instead of forcing open the plunger type valve 19 in the valve unit 20" and flowing out of the body of the valve unit via the sleeve type valve seat 80 flows through the duct 106, the holes I01", the annular groove I04, and the ducts I28 into the centrifugal valve chamber 28. From this chamber the oil flows via the passage Hi8 to the by-pass port 38 in the pump housing I1. 7 As long as the shaft is driven at low speed and the valve plungers I23 are held against the shaft by the springs I25 the pump pumps no oil from the valve unit 20. When the speed of the motor driven shaft increases to such an extent that the centrifugal force or action of the valve plungers I23 is sufficient to collapse the springs I25 the plungers move outwards and close the outer ends of the ducts I28. 'As soon as these ducts are closed by-passing of the oil through the centrifugal pump chamber 28 to the by-pass port 38 ceases and the oil flows from the pump into the pressure chamber 88* and then after opening the plunger type valve 19 flows out of the body of the valve unit 2i!" via the sleeve type valve seat Sil As long as the motor driven shaft rotates,

at such a speed that the valve plungers I23are -in closed relation with respect to the outer ends of theducts I28, the internal gear pump l8 operates to pump oil from the valve unit 20". As soon as the rotational speedof the shaft drops to such an extent that the springs overcome the centrifugal action of the valve plungers and force the valve plungers inwards against the shaft, the pump, due to the by-passing action of the oil, is rendered inoperative. By substituting springs vwith greater or less compression for the springs 125 the pump structure may be set so that pumping of oil from the valve unit 20 is obtained at either higher or lower speeds of the shaft.

The herein described pump structures are comparatively simple as far as construction and design are concerned and may be manufactured at a low and reasonable cost. They are extremely efficient in operation due to the automatic control means.

Whereas the aforementioned pump structures have been described in connection with oil burners and the pumping of oil, it is to be understood that they may be used for other purposes and in connection with the pumping of other liquids.

is not to be restricted to the details set forthg since-these may be modified within the scope of the appended claims, without departing from the spirit and scope of the invention.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

It is also to be understood that. the inventions 1. A pump structure of the character described comprising in combination an elongated housing embodying a pump chamber in one end thereof with a suction'and a pressure side and a second chamber in its other end and having a fluid inlet and an outlet leading respectively tothe suction and pressure sides of said pump chamber, a drive shaft Journaled in the housing so that it extends through the two chambers and having a by-pass forming longitudinal duct therein with one end thereof connected to the pressure side of the pump chamber and its other end communicating with said second chamber, rotary pump means in the-pump chamber connected for drive by the shaft and operative during drive to draw fluid through the inlet and deliver it under pressure to the outlet and said by'-pass forming duct, a valve in said second chamber for controlling said duct, means mounted in said second chamber on the shaft and controlled by the rotative speed of the shaft for automatically closing the aforesaid valve when the shaft reaches a predetermined speed and automatically opening said valve when the shaft drops below a certain speed, and a pressure opening valve disposed in, and operative to control the outflow of fluid through, the outlet and adapted when the duct controlling valve is closed during pump operation and the pressure of the pumped fluid against it is thus increased to open and permit the pumped fluid to flow through the outlet and when said duct controlling valve is opened and the pressure of the fluid against it is thus decreased to close the outlet against outflow of the pumped fluid therethrough.

2. A pump structure of the-character described comprising in combination an elongated housing embodying a pump chamber in one end thereof with a suction and a-pressure side and a second chamber'in its other end and having a fluid inlet and an outlet leading respectively to the suction and pressure sides of said pump chamber, a drive through the two chambers and having a by-pass III forming longitudinal duct therein having one end thereof communicating at all times with the pressure side of the pump chamber and provided at its other end with a cross-hole leading to said second chamber, rotary pump means in the pump chamber connected for drive by the shaft and operative during drive to draw fluid through the inlet and deliver it under pressure to the outlet and said by-passforming duct, a sleeve valve in said second chamber mounted 'slidably on the cross-shaft and adapted when slid in one direction to lap the cross-hole and close the by-pass and when slid in the other direction to expose the cross-hole and open the by-pass, centrifugal governor means mounted in said second chamber on the shaft and controlled by the rotative speed of the latter so that it operates automatically to shift the sleeve valve in said one direction for bypass closing purposes when the shaft reaches a predetermined speed and to shift the sleeve valve in the opposite direction for by-pass opening purposes when the shaft drops below a certain speed, and a spring closed pressure opening valve disposed in, and operative to control the outflow of fluid through, the outlet and adapted when the by-pass is closed'during pump operation and the pressures of the pumped fluid against it is thus increased to open against the force or its spring and permit the pumped fluid to flow through the 

